FaFrit

Using curiosity as the starting point for careful observation of nature and society is a nontrivial skill, and a starting point for new intellectual endeavors and adventures. It is one essential contributor to creativity in science, and a start in forcing new ideas into inflexible professional orthodoxies.

The relative strength of noncovalent interactions between a thioether sulfur atom and various π systems in designed top pan molecular balances was determined by NMR spectroscopy. Compared to its oxygen counterpart, the sulfur atom displays a remarkable ability to interact with almost equal facility over the entire range of π systems studied, with the simple alkene emerging as the most powerful partner. With the exception of the O⋅⋅⋅heteroarene interaction, all noncovalent interactions of sulfur with π systems are favoured over oxygen.

Sulfur tips the balance: The relative strength of noncovalent interactions between a thioether sulfur atom and π systems in molecular balances was determined by NMR spectroscopy. The sulfur atom displays a remarkable ability to interact with almost equal facility over the entire range of π systems studied. With the exception of the O⋅⋅⋅heteroarene interaction, all noncovalent interactions of sulfur with π systems are favoured over oxygen.

Black phosphorus intercalation compounds (BPICs) with alkali metals (namely: K and Na) have been synthesized in bulk by solid-state as well as vapor-phase reactions. By means of a combination of in situ X-ray diffraction, Raman spectroscopy, and DFT calculations the structural behavior of the BPICs at different intercalation stages has been demonstrated for the first time. Our results provide a glimpse into the very first steps of a new family of intercalation compounds, with a distinct behavior as compared to its graphite analogues (GICs), showing a remarkable structural complexity and a dynamic behavior.

Black to the future: The bulk intercalation of black phosphorus with alkali metals (namely: K and Na; black spheres) has been developed, showing a complex dynamic structural behavior. By in situ Raman spectroscopy and DFT calculations straightforward fingerprints for the identification of black phosphorus intercalation compounds (BPICs) have been demonstrated.

A multiply interlocked catenane with a novel molecular topology was synthesized; a phthalocyanine bearing four peripheral crown ethers was quadruply interlocked with a cofacial porphyrin dimer bridged with four alkylammonium chains. The supramolecular conjugate has two nanospaces surrounded by a porphyrin, a phthalocyanine, and four alkyl chains to accommodate guest molecules. Because the phthalocyanine can move along the alkyl chains, it acts as an adjustable wall, thus permitting the invasion of large molecules into the nanospaces without spoiling the affinity of the association. The dynamic molecular invasion allowed the intercalation of dianionic porphyrins into both nanospaces with high affinity. A photometric titration experiment revealed the two-step inclusion phenomenon. The multiply interlocked catenane complexed with three Cu²⁺ ions, and the spin–spin interaction was switched off by the intercalation of dianionic porphyrins.

An elevator for guests: A phthalocyanine molecule bearing four peripheral crown ethers was quadruply interlocked with a cofacial porphyrin dimer bridged by four alkylammonium chains to create a catenane with a novel topology. The phthalocyanine unit moved along the threads to enable the invasion of large guest molecules without affecting the affinity of the association (see picture).